Extraction and Characterization of Cellulosic Fibers from Jenfokie and Doby Stems: Effect of Extraction Methods on Physicochemical, Mechanical, and Thermal Properties

This experimental study aims to explore natural lignocellulosic fibers from Jenfokie and Doby plants. The effect of the fiber (water-retted and non-retted) extraction methods on physical, mechanical, thermal, chemical, and crystallinity properties were experimentally investigated for fibers collected from the eastern highlands of Ethiopia. The chemical composition (cellulose, hemicellulose, lignin, extractives, etc.) was determined after different treatment processes. The tensile strength maximum of up to 72 cN/tex and 56 cN/tex, and cellulose content up to 85% and 81% were obtained for Jenfokie and Doby retted extracted fibers, respectively. There was small difference lignin extracted by Klason method and the alkaline hydrogen peroxide (APH) method. Each step-wise extracted fiber was characterized to cognize the intrinsic changes during the multi-step extraction process. The diameters were determined by Optical Microscope (OM), the removal of non-cellulosic materials by Fourier Transform Infrared (FT-IR) spectroscopy, the thermal stability (up to 375°C) by thermogravimetry (TGA), and the crystallinity index (up to 73%) by using X-ray Diffraction (XRD). An improvement in cellulose content, density, moisture absorption, tensile strength, thermal stability, and crystallinity of Jenfokie (unstudied or new) and Doby plant retted fibers would be promising for composite and textile materials

Extraction and Characterization of Fiber and Cellulose from Ethiopian Linseed Straw: Determination of Retting Period and Optimization of Multi-Step Alkaline Peroxide Process

Flax is a commercial crop grown in many parts of the world both for its seeds and for its fibers. The seed-based flax variety (linseed) is considered less for its fiber after the seed is extracted. In this study, linseed straw was utilized and processed to extract fiber and cellulose through optimization of retting time and a multi-step alkaline peroxide extraction process using the Taguchi design of experiment (DOE). Effects of retting duration on fiber properties as well as effects of solvent concentration, reaction temperature, and time on removal of non-cellulosic fiber components were studied using the gravimetric technique, Fourier transform infrared (FTIR) spectroscopy and thermal studies. Based on these findings, retting for 216 h at room temperature should offer adequate retting efficiency and fiber characteristics; 70% cellulose yield was extracted successfully from linseed straw fiber using 75% ethanol–toluene at 98 °C for 4 h, 6% NaOH at 75 °C for 30 min, and 6% H2O2 at 90 °C for 120 min

Synthesis and Characterization of High Surface Area Transparent SiOC Aerogels from Hybrid Silicon Alkoxide: A Comparison between Ambient Pressure and Supercritical Drying

In this article, highly porous and transparent silicon oxycarbide (SiOC) gels are synthesized from Bis(Triethoxysilyl) methane (BTEM). The gels are synthesized by the sol-gel technique followed by both ambient pressure and supercritical drying. Then, the portion of wet gels have been pyrolyzed in a hydrogen atmosphere at 800 and 1100 °C. The FT-IR spectroscopy analysis and nitrogen sorption results indicate the successful synthesis of Si-O-Si bonds and the formation of mesopores. From a hysteresis loop, the SiOC ceramics showed the H1 type characteristic with well-defined cylindrical pore channels for the aerogel and the H2 type for the ambigel samples, indicating that the pores are distorted due to the capillary stress. The produced gels are mesoporous materials having high surface areas with a maximum of 1140 m2/g and pore volume of 2.522 cm3/g obtained from BTEM aerogels. The pyrolysis of BTEM aerogels at 800 °C results in the production of a bulk and transparent sample with a slightly pale white color, while BTEM xerogels are totally transparent and colorless at the same temperature. At 1100 °C, all the aerogels become opaque brown, confirming the formation of free carbon and crystalline silicon

Ethyl 27-oxo-15-oxa-2,20-diazahexacyclo[18.6.1.01,8.02,6.09,14.021,26]heptacosa-9,11,13,21,23,25-hexaene-7-carboxylate

In the title compound, C27H30N2O4, the pyrrolidine ring adopts a twisted conformation. The indoline ring system is almost perpendicular to the mean plane of the pyrrolidine ring, making a dihedral angle of 81.7 (8)°. In the crystal, molecules are linked into centrosymmetric dimers with graph-set motif R22(16) via pairs of C—H...O hydrogen bonds. The terminal ethyl group of the ester group is disordered over two sets of sites, with a site-occupancy ratio of 0.587 (11):0.413 (11)